Single mode fiber optic cable is made up of a small diameter glass or plastic core surrounded by cladding, which is a layer of reflective material. In fiber-optic communication, a single-mode optical fiber, also known as fundamental- or mono-mode, is an optical fiber designed to carry only a single mode of light - the transverse mode. Although they can do the same job in some instances, the different construction methods make each of them better suited to certain tasks and budgets. That makes picking between single mode and multimode fiber optic cables an. Network cables, known as fiber optics, allow data to be transmitted using pulses of light that travel along the fiber. This small core permits only one light mode to propagate through.